Fluid-actuated valve



March 4, 1930. DRATH 1,749,695

FLUID ACTUATED VALVE Filed July 27. 1926 Patented Mar. 4, 1930 RAIMUND DEATH, OF GRUNAU, BERLIN, GERMANY FLUID-ACTUATED VALVE I Application filed July 27, 1926, Serial No.

The subject of this invention is a controlling device for machines such as prime movers, steam pumps and the like, having reciprocating pistons, the said device being part-icularly intended for use with such machines which are made without flywheels. The purpose of the invention is to produce a controlling device which is simple in construction and reliable in action.

According to this invention the controlling member is a slide valve in the form of a differential piston having two ends of different diameters, the terminal surfaces and an inwardly presented annular surface near the larger end serving as .pressure surfaces. The parts of the piston at each end are shaped like a spool or bobbin, that is to say they are provided with annular grooves to pass across the inlets through which live steam or other pressure medium arrives, so that the ducts through which the pressure medium is admitted to the Working cylinder are completely separated from the ducts through which it is admitted to the pressure surfaces of the controlling slide valve. Therefore no unintentional flowing over of driving medium prejudicial to the running of the machine can take place from the controlling ducts to the working cylinder at the side connected with the exhaust till shortly before the end of the stroke. The machine COIISBtglGIItlY works satisfactorily under a small loa In the accompanying drawings or diagrams Figure 1 is a vertical section representing the controlling piston in its rlght hand terminal position. Figure 2 is a vertical section representing the controlling piston in its left hand terminal position.

The controlling piston P is double ended. comprising practically two pistons p,p,each of which is made spool or bobbin shaped with a deep circumferential groove or recess (F, F). The steam or pressure medium inlet pipe or duct S has two branches S and S to which the grooves F and F are respectively opened in the travel of the piston. The pressure surfaces are the terminal faces a and c, and the annular surface I), the last named surface being exposed to pressure (at appropriate times, as hereinafter described) 125,274, and in Germany August 1, 1925.

in the inner end of the chamber R, in which chamber the larger end portion p of the piston works. The working cylinder W, in which the piston T reciprocates, is adapted to receive steam or pressure medium through the pipes or ducts A and A in turn, by way of the grooves F and F respectively. Outlet pipes or ducts B, B are adapted to establish communication between the working cylinder W and the exhaust chamber e, which latter is provided with an exhaust pipe or duct E open to the atmosphere; the said pipe B can be put in communication with the chamber 6 by way of the chamber R and duct D. The pressure medium to operate the controlling piston P is supplied from the working cylinder W through the pipes or ducts G, C which are bifurcated in order to ensure smooth working of the piston P. The outlet pipe B has also a branch B connecting 7 it with the aforesaid chamber R.

The method of operation of the controlling device is as follows :Referring firstly to Figure 1, live steam or other pressure medium flows through the left branch 8 of the steam pipe S, the annular groove F of the controlling piston and the inlet duct A and drives the working piston T to the right. The pressure medium passing through the controlling duct C out of the working cylinder into the chamber in front of the surface a holds the controllingslide valve in the right terminal position. The high tension driving medium passing through the duct 13 on. to the annular surface I) is not able to reverse the controlling slide valve, because the annular surface 6 is smaller than the surface a. The spent driving medium to the right of the working piston escapes through the duct B and through the duct D to the exhaust E. As soon as the working piston upon its path to the right has passed beyond the opening of the duct 0 it closes the opening of the exhaust duct B At the right end of the working cylinder there consequently ensures a compression favourable to a change in the stroke. Through the controlling duct C high pressure steam passes from A and the working cylinder to the right terminal surface 0 of the controlling slide valve. The

driving medium pressure exerted upon the surface a now acts in the direction from left to right while the pressure exerted upon the surfaces 0 and 6 acts from ri ht to left. The sum total of the surfaces b an o is greator than the surface a. Consequently the displacement of the controlling slide valve to the left now takes place, allowing the influx of driving medium upon the right side of the working piston. The driving medium already used and located to the left of the working piston flows over the duct B and the exhaust E into the open air. The annular surface I) is also connected with the open air through E, B and E. When the working piston has reached the end of its stroke to the left, high pressure driving medium flows through the duct C to the surface a, the annular surface 6 is free from pressure, and the terminal surface ois also through the duct C under the pressure of high tension driving medium. As the surface a is greater than c hence the displacement of the controlling slide valve again takes place to the right.

What I claim and deslre to secure by Letters Patent of the United States is In a valve gear for reci rocating engines, a casing having two fluid a IIlISSlOIl chambers A of difi'erent diameters and an exhaust chamber intermediate the two fluid admission chambers, an open exhaust pipe leading therefrom, a control valve in the form of a differential piston having at each end two discs separated by a groove, one pair of discs being of a larger dlameter than the other pair, the area of the small end face, together with an annular surface situated on the inner side of the larger pair of discs being greater than the area of the larger end face, a working cylinder, a piston located therein, three valve control conduits leading from each fluid admission chamber to the working cylinder at its ends respectively and adapted to be opened and closed by the differential piston substantially as shown.

RAIMUND DEATH. 

